Three axis magnetic sensor device and method

ABSTRACT

A method and structure for a three-axis magnetic field sensing device is provided. The device includes a substrate, an IC layer, and preferably three magnetic field sensors coupled to the IC layer. A nickel-iron magnetic field concentrator is also provided.

BACKGROUND OF THE INVENTION

This invention relates generally to integrated devices. Morespecifically, the invention provides an integrated transducer apparatusthat can be used in combination with other Micro-electromechanicalsystems (MEMS) devices, but can have other uses as well. For example,the MEMS devices can provide an accelerometer, an angular rate sensor, amagnetic field sensor, a pressure sensor, a microphone, a humiditysensor, a temperature sensor, a chemical sensor, a biosensor, aninertial sensor, and others.

Research and development in integrated microelectronics have continuedto produce progress in CMOS and MEMS technology. CMOS technology hasbecome the predominant fabrication technology for integrated circuits(ICs). In layman's terms, the ICs are the “brains” of an integrateddevice and provide decision-making capabilities, while MEMS are the“eyes” and “arms” and provide the ability to sense and control theenvironment. Some examples of the widespread application of thesetechnologies are the switches in radio frequency (RF) antenna systems,such as those in the iPhone™ or iPad™ device by Apple, Inc. ofCupertino, Calif. and the Blackberry™ phone by Research In MotionLimited of Waterloo, Ontario, Canada. They are also used to provideaccelerometers in sensor-equipped game devices, such as those in theWii™ controller manufactured by Nintendo Company Limited of Japan.Though they are not always easily identifiable, these technologies arebecoming more prevalent every day.

Beyond consumer electronics, use of IC and MEMS technology hasapplications through modular measurement devices such as accelerometers,angular rate sensors, actuators, and other sensors. In conventionalvehicles, accelerometers and angular rate sensors are used to deployairbags and trigger dynamic stability control functions, respectively.MEMS angular rate sensors can also be used for image stabilizationsystems in video and still cameras, automatic steering systems inairplanes and guided munitions, or the like. MEMS can also be in theform of biological MEMS (Bio-MEMS) that can be used to implementbiological and/or chemical sensors for Lab-On-Chip applications. Suchapplications may integrate one or more laboratory functions on a singlemillimeter-sized chip. Other applications include Internet and telephonenetworks, security and financial applications, and health care andmedical systems. As described previously, ICs and MEMS can be used topractically engage in various type of environmental interaction.

Although highly successful, ICs and in particular magnetic field sensorsand MEMS still have limitations. Similar to IC development, magneticsensor and MEMS development, which focuses on increasing performance,reducing size, and decreasing cost, continues to be challenging.Additionally, applications of magnetic sensors and MEMS often requireincreasingly complex microsystems that desire greater computationalpower. Unfortunately, such applications generally do not exist. Theseand other limitations of conventional magnetic sensors, MEMS, and ICsmay be further described throughout the present specification and moreparticularly below.

From the above, it is seen that techniques for improving operation ofintegrated circuit devices, magnetic field sensors, and MEMS are highlydesired.

BRIEF SUMMARY OF THE INVENTION

According to embodiments of the present invention, techniques generallyrelated to integrated devices and systems are provided. In particular,embodiments of the present invention provide a method and structure forfabricating a three-axis magnetic field sensing device. Morespecifically, embodiments of the present invention provide methods forforming at least a first, second, and third magnetic field sensorelement overlying a substrate member with field concentrator(s) andoperably coupled to an integrated circuit (IC) layer. Merely by way ofexample, the magnetic field sensor elements can include ordinarymagneto-resistive (OMR) device(s), anisotropic magneto-resistive (AMR)devices, giant magneto-resistive (GMR) device(s), tunnel junctionmagneto-resistive (TMR), or others. Additionally, other applicationsinclude at least a sensor application or magnetic field sensingapplications, system applications, among others. But it will berecognized that the invention has a much broader range of applicability.

Embodiments of the present invention include a method includingproviding a substrate having a surface region. The substrate can have atleast one portion removed via an etching process or other processes. Atleast one nickel iron (NiFe) material can be formed overlying at least aportion of the surface region. At least one dielectric material and atleast one metal material can be formed overlying the surface region aswell. The dielectric material(s) and metal material(s) can form magneticfield sensor elements, an IC layer, or other magnetic field sensordevice component. A passivation material can be formed overlying theseother materials.

Embodiments of the device can have a substrate member including asurface region. The substrate can have at least one portion removed viaan etching process or other processes. An IC layer can be spatiallydisposed overlying at least a portion of the surface region of thesubstrate member. A first, second, and third magnetic field sensorelement can be operably coupled to the IC layer. Each of the magneticfield sensor elements can include a first material and be configured todetect at least in single direction. Also, at least one magnetic fieldconcentrator can be spatially disposed overlying at least a portion ofthe surface region.

Many benefits are achieved by way of embodiments the present inventionover conventional techniques. For example, embodiments of the presenttechnique provide an easy to use process to integrate a three-axismagnetic field sensor on a single die. In some embodiments, the methodprovides higher device yields in dies per wafer with the integratedapproach. Additionally, the method provides a process and system thatare compatible with conventional semiconductor and MEMS processtechnologies without substantial modifications to conventional equipmentand processes. Preferably, the invention provides for an improvedmagnetic field sensor or magnetic field sensor device system and relatedapplications for a variety of uses. In one or more embodiments, thepresent invention provides for all magnetic field sensors, and relatedapplications, which may be integrated on one or more semiconductordevice structures. Depending upon the embodiment, one or more of thesebenefits may be achieved. These and other benefits will be described inmore throughout the present specification and more particularly below.

Various additional objects, features and advantages of the presentinvention can be more fully appreciated with reference to the detaileddescription and accompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

These diagrams are merely an example, which should not unduly limit thescope of the claims herein. One of ordinary skill in the art wouldrecognize many other variations, modifications, and alternatives. It isalso understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the spirit and purview of this process and scopeof the appended claims.

FIG. 1 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention;

FIG. 2 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention;

FIG. 3 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention;

FIG. 4 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention;

FIG. 5 is a simplified flow diagram of a method for fabricating a devicefor sensing magnetic fields according to an embodiment of the presentinvention;

FIG. 6 is a simplified flow diagram of a method for fabricating a devicefor sensing magnetic fields according to an embodiment of the presentinvention;

FIG. 7 is a simplified cross-sectional diagram of a device for sensingmagnetic fields according to an embodiment of the present invention;

FIG. 8 is a simplified cross-sectional diagram of a device for sensingmagnetic fields according to an embodiment of the present invention;

FIG. 9 is a simplified cross-sectional diagram of a device for sensingmagnetic fields according to an embodiment of the present invention; and

FIG. 10 is a simplified cross-sectional diagram of a device for sensingmagnetic fields according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

According to embodiments of the present invention, techniques relatedgenerally to integrated devices and systems are provided. In particular,embodiments of the present invention provide methods and structures fora three-axis magnetic field sensing device. More specifically,embodiments of the present invention provide methods for forming atleast one a first, second, and third magnetic field sensor elementoverlying a substrate member with field concentrator(s) and operablycoupled to an integrated circuit (IC) layer. Merely by way of example,the magnetic field sensor elements can include ordinarymagneto-resistive (OMR) device(s), anisotropic magneto-resistive (AMR)devices, giant magneto-resistive (GMR) device(s), tunnel-junctionmagneto-resistive (TMR), or others. Additionally, other applicationsinclude at least a sensor application or magnetic field sensingapplications, system applications, among others.

FIG. 1 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention. Thisdiagram, which can represent a partially formed three-axis magneticfield sensor device or a two-axis magnetic field sensor device, ismerely an example, which should not unduly limit the scope of the claimsherein. One of ordinary skill in the art would recognize many othervariations, modifications, and alternatives. As shown, device 100includes a substrate 110, an integrated circuit (IC) layer 120, a firstmagnetic field sensor element 130, and a second magnetic field sensorelement 140.

In an embodiment, substrate 110 can have a surface region. In a specificembodiment, substrate 110 can include a buried oxide (BOX) substrate.Substrate 110 can include a substrate-on-insulator (SOI) substrate. Inanother specific embodiment, substrate 110 can include an epitaxial(EPI) material. In further embodiments, substrate 110 can have asilicon, single crystal silicon, or polycrystalline silicon material.Substrate 110 can also include metals, dielectrics, polymers, and othermaterials and combinations thereof.

In an embodiment, IC layer 120 can be formed overlying at least oneportion of the surface region. In a specific embodiment, IC layer 120can include an application specific integrated circuit (ASIC) layer, orother type of IC layer or combination thereof. Also, IC layer 120 caninclude at least one IC device, CMOS device, or other device. IC layer120 can be coupled to the first and second magnetic field sensorelements 130 and 140.

In an embodiment, first magnetic field sensor element(s) 130 and secondmagnetic field sensor element 140 can be formed overlying at least oneportion of the surface region. Magnetic field sensor elements 130 and140 can include ordinary magneto-resistive (OMR) device(s), anisotropicmagneto-resistive (AMR) device(s), giant magneto-resistive (GMR)device(s), or tunnel junction magneto-resistive (TMR) device(s).Elements 130 and 140 can also be other types of magnetic field sensordevices, sensors, or combinations thereof. In a specific embodiment,magnetic field sensor elements 130 and 140 can include thin film devicesthat can be deposited overlying at least one portion of the surfaceregion. The thin film device(s) can be deposited by a sputtering processor an electric plating process. In a specific embodiment, magnetic fieldsensor elements 130 and 140 are formed as a Wheatstone bridge, a halfbridge, or a single element configuration. In an embodiment, magneticfield sensor elements 130 and 140 can include at least one layer ofdielectric material and/or metal material.

FIG. 2 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention. Thisdiagram, which can represent a three-axis magnetic field sensor device,is merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize manyother variations, modifications, and alternatives. As shown, device 200includes a substrate 110, an integrated circuit (IC) layer 120, at leastone first magnetic field sensor element 130, at least one secondmagnetic field sensor element 140, and at least one third magnetic fieldsensor element 150. FIG. 2 shows the third magnetic field sensor elementin a configuration that is parallel to the first magnetic field sensorelement(s).

In an embodiment, substrate 110 can have a surface region. In a specificembodiment, substrate 110 can include a buried oxide (BOX) substrate.Substrate 110 can include a substrate-on-insulator (SOI) substrate. Inanother specific embodiment, substrate 110 can include an epitaxial(EPI) material. In further embodiments, substrate 110 can have asilicon, single crystal silicon, or polycrystalline silicon material.Substrate 110 can also include metals, dielectrics, polymers, and othermaterials and combinations thereof.

In an embodiment, IC layer 120 can be formed overlying at least oneportion of the surface region. In a specific embodiment, IC layer 120can include an application specific integrated circuit (ASIC) layer, orother type of IC layer or combination thereof. Also, IC layer 120 caninclude at least one IC device, CMOS device, or other device. IC layer120 can be coupled to the magnetic field sensor elements 130, 140, and150.

In an embodiment, first magnetic field sensor element(s) 130, secondmagnetic field sensor element 140, and third magnetic field sensorelement 150 can be formed overlying at least one portion of the surfaceregion. Magnetic field sensor elements 130, 140, and 150 can includeordinary magneto-resistive (OMR) device(s), anisotropicmagneto-resistive (AMR) device(s), giant magneto-resistive (GMR)device(s), or tunnel junction magneto-resistive (TMR) device(s).Elements 130, 140, 150 can also be other types of magnetic field sensordevices, sensors, or combinations thereof. In a specific embodiment,magnetic field sensor elements 130, 140, and 150 can include thin filmdevices that can be deposited overlying at least one portion of thesurface region. The thin film device(s) can be deposited by a sputteringprocess or an electric plating process. In a specific embodiment,magnetic field sensor elements 130, 140, and 150 are formed as aWheatstone bridge, a half bridge, or a single element. In an embodiment,magnetic field sensor elements 130, 140, 150 can include at least onelayer of dielectric material and/or metal material.

Integrating a three-axis magnetoresistive (MR) sensor device on a singlechip has been challenging because thin film MR sensors are onlysensitive to the magnetic field parallel to the plane of the thin film.This limitation is due to the strong shape anisotropic field in the outof plane direction. The magnetic thin film also has a crystalanisotropic field, which makes the crystal anisotropic easy direction apreferred configuration for the sensors.

In an embodiment, the design of a single chip 3-axis magnetic sensordevice can be based on magneto-resistive technologies including, but notlimited to, Anisotropic Magneto-Resistive (AMR), Giant Magneto-Resistive(GMR), and Tunnel Magneto-Resistive (TMR) effects. In a specificembodiment, a vertical field can be channeled to magnetic thin filmplane through a field (flux) concentrator, which can be used effectivelyas a Z-field sensor.

The Z-field sensor can be designed in any orientation on the thin filmplane. For example, the sensor can be designed to have the best sensorperformance, such as being configured in a sensitive direction on thecrystal hard axis to have lower electric/magnetic noise, or aligned withX or Y sensors for easy calibration. The Z-axis sensor can be designedto be a gradient magnetic field sensor, making it highly insensitive toany uniformly applied field on the horizontal plane. This design cancause the Z-axis sensor's output to be proportional to the Z-axis fieldchanneled through field (flux) concentrator. However, due tomanufacturing imperfection and tolerance, the four elements (or twoelements for half bridge) of Z-axis sensor might not be perfectlyidentical or symmetrical to the field (flux) concentrator elements. Insome cases, the field (flux) concentrator element may not be identical,which may require calibration of the concentrators to the substratebecause the horizontal field may influence the Z-axis sensorperformance.

For horizontal X-Y configurations, the sensors can be configured asWheatstone bridges or half bridges with four elements. The sensitivedirection of the x-axis sensor is 45 degrees away from the crystalanisotropic easy axis direction of the substrate, and the sensitivedirection of the y-axis sensor is −45 degrees of the crystal easy axis.The X and Y sensors can be configured to be symmetrical to the crystalhard axis in order to match the sensor's sensitivities.

By using a single Set/Reset strap (shown as the material formed in aspiral shape underneath the sensors in FIGS. 1-3) for X-Y sensors, themagnetization of both X and Y sensors will be aligned uponinitialization. As a current pulse passes through the Set/Reset strap, alocalized magnetic field is generated on the sensor elements right aboveor below the strap. In various embodiments, the pulse current is strongenough to align magnetic domains in the MR sensor elements substantiallyto its field direction. Upon releasing the pulse current, magnetizationof X-Y sensors relax to their easy axis directions of their totalanisotropic field, and form sensitivities in the x-axis or y-axisdirection. The X-Y Sensors are field sensors, which means the outputvoltage is proportional the magnetic field strength in their sensitivedirections.

Z sensor can share the set/reset strap with the X-Y sensors. Z sensor isa gradient sensor, which means the output voltage is proportional to thefield differences along its sensitive direction. Z sensor can beparallel to the x-axis sensor, the y-axis sensor, or in the differentorientation altogether.

FIG. 3 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention. Thisdiagram, which can represent a three-axis magnetic field sensor device,is merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize manyother variations, modifications, and alternatives. As shown, device 300includes a substrate 110, an integrated circuit (IC) layer 120, at leastone first magnetic field sensor element 130, at least one secondmagnetic field sensor element 140, and at least one third magnetic fieldsensor element 150. FIG. 3 shows the third magnetic field sensorelement(s) 150 in a configuration that is parallel to the secondmagnetic field sensor element(s) 140. A detailed description of thecomponents of device 300 can be found in the description above for FIG.2.

FIG. 4 is a simplified top diagram of a device for sensing magneticfields according to an embodiment of the present invention. Thisdiagram, which can represent a three-axis magnetic field sensor device,is merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize manyother variations, modifications, and alternatives. As shown, device 400includes a substrate 110, an integrated circuit (IC) layer 120, a firstmagnetic field sensor element 130, a second magnetic field sensorelement 140, and a third magnetic field sensor element 150. FIG. 4 showsthe third magnetic field sensor element in a configuration that isaligned to a crystal easy axis. A detailed description of the componentsof device 400 can be found in the description above for FIG. 2.

FIG. 5 is a simplified flow diagram illustrating a method of fabricatinga device for sensing magnetic fields according to an embodiment of thepresent invention.

As shown in FIG. 5, the present method can be briefly outlined below.

1. Start;

2. Provide a substrate member having a surface region;

3. Remove at least one portion of the substrate

4. Form an integrated circuit (IC) layer;

5. Form magnetic field sensor elements;

6. Form at least one field concentrator;

7. Form passivation material(s); and

8. Stop.

These steps are merely examples and should not unduly limit the scope ofthe claims herein. As shown, the above method provides a way offabricating a three-axis magnetic field sensing device, which can bemonolithically integrated with signal condition ASIC(s), according toembodiments of the present invention. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.For example, various steps outlined above may be added, removed,modified, rearranged, repeated, and/or overlapped, as contemplatedwithin the scope of the invention.

As shown in FIG. 5, method 500 begins at start, step 502. The presentembodiment provides a fabrication method for forming a three-axismagnetic field sensing device monolithically integrated, which can beintegrated with its signal condition ASIC(s). Many benefits are achievedby way of the present invention over conventional techniques. Forexample, the present technique provides an easy to use process thatrelies upon conventional semiconductor and MEMS technologies. In someembodiments, the method provides a low cost way to manufacture athree-axis magnetic field sensor on a single die. Additionally,embodiments of the method provide a process and system that arecompatible with conventional process technology without substantialmodifications to conventional equipment and processes. Preferably,embodiments of the invention provide for an improved sensors andelectronic devices and related methods for a variety of uses. Dependingupon the embodiment, one or more of these benefits may be achieved.These and other benefits will be described in more throughout thepresent specification and more particularly below.

Following step 502, fabrication method 500 involves providing asubstrate having a surface region, step 504. The substrate can include asubstrate-on-insulator (SOI) substrate. In specific embodiment, thesubstrate can include an epitaxial (EPI) material. In furtherembodiments, the substrate can have a silicon, single crystal silicon,or polycrystalline silicon material. The substrate can also includemetals, dielectrics, polymers, and other materials and combinationsthereof. Those skilled in the art will recognize other variations,modifications, and alternatives.

At least one portion of the substrate can be removed, step 506 to formlateral surfaces. In an embodiment, the removal of portion(s) of thesubstrate can include a wet etching, dry etching, or mechanical process.In a specific embodiment, the removal of portion(s) of the substrate caninclude a deep reactive-ion etching (DRIE) process. The removal processcan include other processes and combinations thereof.

An integrated circuit (IC) layer can be formed overlying at least oneportion of the surface region, step 508. In a specific embodiment, theIC layer can include an application specific integrated circuit (ASIC)layer, or other type of IC layer or combination thereof. Also, the IClayer can include at least one IC device, CMOS device, or other device.In various embodiments, the IC layer can be coupled to the magneticfield sensor elements.

In an embodiment, magnetic field sensor elements can be formed overlyingat least one portion of the surface region, step 510. In a specificembodiment, the magnetic field sensor elements can include at least onefirst magnetic field sensing element, at least one second magnetic fieldsensing element, and at least one third magnetic field sensing element.These magnetic field sensor elements can include ordinarymagneto-resistive (OMR) device(s), anisotropic magneto-resistive (AMR)device(s), giant magneto-resistive (GMR) device(s), or tunnel junctionmagneto-resistive (TMR) device(s). Also, these magnetic field sensorelements can be manufactured in one process or a combination ofprocesses. These elements can also be other types of magnetic fieldsensor devices, sensors, or combinations thereof. In a specificembodiment, these magnetic field sensor elements can include thin filmdevices that can be deposited overlying at least one portion of thesurface region. The thin film device(s) can be deposited by a sputteringprocess or an electric plating process. In a specific embodiment, thesemagnetic field sensor elements can be formed as a Wheatstone bridge, ahalf bridge, or a single element. In an embodiment, these magnetic fieldsensor elements can include at least one layer of dielectric materialand/or metal material.

After forming the magnetic field sensor element(s), at least onemagnetic field concentrator can be formed overlying at least one portionof the surface region, step 512. In a specific embodiment, the magneticfield concentrator(s) can include a nickel-iron material. The magneticfield concentrator(s) can also include other materials, compositions,and combinations thereof. The magnetic field concentrator(s) can includemagnetic field concentrator(s) that includes a permalloy material, whichcan be a nickel iron (NiFe) or a nickel iron cobalt (NiFeCo) material.In various embodiments, permalloy may include a nickel iron magneticalloy typically having about 20% iron and 80% nickel content.” In aspecific embodiment, the magnetic field concentrator(s) can be formedvia an electric plating process or sputtering process. Then, apassivation material can be formed overlying at least the magnetic fieldsensor element(s), step 514. As stated, there can be other variations,modifications, and alternatives.

The above sequence of processes provides a fabrication method forforming sensors or electronic devices integrated with fieldconcentrators according to an embodiment of the present invention. Asshown, embodiments of the method disclose a combination of stepsincluding providing a substrate, removing at least one portion of thesubstrate, forming an insulating material overlying at least one portionof the substrate, forming magnetic field sensor element(s) and magneticfield concentrator(s), and forming a passivation material overlying atleast the magnetic field sensor element(s). Other alternatives can alsobe provided where steps are added, one or more steps are removed, or oneor more steps are provided in a different sequence without departingfrom the scope of the claims herein. Further details of the presentmethod can be found throughout the present specification.

FIG. 6 is a simplified flow diagram illustrating a method of fabricatinga device for sensing magnetic fields.

As shown in FIG. 6, the present method can be briefly outlined below.

1. Start;

2. Provide a substrate member having a surface region;

3. Form at least one insulation material overlying the surface region;

4. Form at least one permalloy material overlying the insulationmaterial(s);

5. Form at least one first metal material overlying the permalloymaterial(s);

6. Form a first dielectric material overlying the first metalmaterial(s);

7. Form at least one second metal material overlying the firstdielectric;

8. Form a second dielectric material overlying the second metalmaterial(s);

9. Form at least one third metal material overlying the seconddielectric material;

10. Form a passivation material overlying the third metal material; and

11. Stop.

These steps are merely examples and should not unduly limit the scope ofthe claims herein. As shown, the above method provides a way offabricating a three-axis magnetic field sensing device according toembodiments of the present invention. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.For example, various steps outlined above may be added, removed,modified, rearranged, repeated, and/or overlapped, as contemplatedwithin the scope of the invention.

As shown in FIG. 6, method 600 begins at start, step 602. The presentembodiment provides a fabrication method for forming a three-axismagnetic field sensing device. Many benefits are achieved by way of thepresent invention over conventional techniques. For example, the presenttechnique provides an easy to use process that relies upon conventionalsemiconductor and MEMS technologies. In some embodiments, the methodprovides a low cost way to manufacture a three-axis magnetic fieldsensor on a single die. Additionally, embodiments of the method providea process and system that are compatible with conventional processtechnology without substantial modifications to conventional equipmentand processes. Preferably, embodiments of the invention provide for animproved sensors and electronic devices and related methods for avariety of uses.

Following step 602, fabrication method 600 involves providing asubstrate having a surface region, step 604. The substrate can include asubstrate-on-insulator (SOI) substrate. In specific embodiment, thesubstrate can include an epitaxial (EPI) material. In furtherembodiments, the substrate can have a silicon, single crystal silicon,or polycrystalline silicon material. The substrate can also includemetals, dielectrics, polymers, and other materials and combinationsthereof. At least one insulation material can be formed overlying atleast one portion of the surface region, step 606. The insulationmaterial(s) can be formed from dielectric materials, oxide materials, orother materials and combinations thereof.

At least one permalloy material can be formed overlying the insulationmaterial(s), step 608. In a specific embodiment, the permalloymaterial(s) can include a nickel iron (NiFe) material a nickel ironcobalt (NiFeCo) material, or other permalloy material or combinationthereof. In various embodiments, permalloy may include a nickel ironmagnetic alloy typically having about 20% iron and 80% nickel content.”In a specific embodiment, the permalloy material(s) can be formed via anelectric plating process or sputtering process.

At least one first metal material can be formed overlying at least oneportion of the permalloy material(s) and the surface region, step 610.The first metal material(s) can include aluminum, or copper, or a metalalloy, other metal material or combination thereof. A first dielectricmaterial can be formed overlying the first metal material(s) and thesurface region, step 612. The first dielectric material can include asilicon oxide material, or other oxide material, or combination thereof.At least one second metal material can be formed overlying at least oneportion of the first dielectric material, step 614. The second metalmaterial(s) can include materials similar to those in the first metalmaterial(s).

A second dielectric material can be formed overlying the second metalmaterial(s) and at least one portion of the first dielectric material,step 616. The third dielectric material can include materials found inthe dielectric materials mentioned previously. At least one third metalmaterial, which can include similar materials used in the metalmaterials mentioned previously, can be formed overlying at least aportion of the fourth dielectric material, step 618. At least onepassivation material can then be formed overlying the third metalmaterial(s) and the second dielectric material, step 620. Thepassivation material(s) can include dielectric materials, oxidematerials, or silicon materials, or other materials or combinationsthereof.

The above sequence of processes provides a fabrication method forforming a three-axis magnetic field sensing device according to anembodiment of the present invention. As shown, embodiments of the methoddisclose a combination of steps including providing a substrate, formingpermalloy materials, forming metal materials, forming dielectricmaterials, and forming passivation materials. Other alternatives canalso be provided where steps are added, one or more steps are removed,or one or more steps are provided in a different sequence withoutdeparting from the scope of the claims herein.

FIG. 7 is a simplified side diagram of a sensor device or electronicdevice according to an embodiment of the present invention. This diagramis merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize manyother variations, modifications, and alternatives. As shown, device 700includes a substrate 710, insulation material(s) 720, permalloymaterial(s) 730, metal materials {740, 760, 780}, dielectric materials{750,780}, and passivation material(s) 790.

In an embodiment, substrate 710 can include a substrate-on-insulator(SOI) substrate. In specific embodiment, the substrate can include anepitaxial (EPI) material. In further embodiments, substrate 710 can havea silicon, single crystal silicon, or polycrystalline silicon material.Substrate 710 can also include metals, dielectrics, polymers, and othermaterials and combinations thereof. Insulation material(s) 720 caninclude dielectric materials, oxide materials, silicon materials, orother materials and combinations thereof.

In a specific embodiment, permalloy material(s) 730 can include a nickeliron (NiFe) material, a nickel iron cobalt (NiFeCo) material, or otherpermalloy material or combination thereof. According to Wikipedia,“permalloy is a term for a nickel iron magnetic alloy typically havingabout 20% iron and 80% nickel content.” Permalloy material(s) 730 can beformed via an electric plating process or sputtering process.

In an embodiment, at least one first metal material 740 can be formedoverlying at least one portion of permalloy material(s) 730 and thesurface region. First metal material(s) 740 can include aluminum, orcopper, or a metal alloy, other metal material or combination thereof. Afirst dielectric material 750 can be formed overlying the first metalmaterial(s) and the surface region. First dielectric material 750 caninclude a silicon oxide material, or other oxide material, orcombination thereof. At least one second metal material 760 can beformed overlying at least one portion of first dielectric material 750.Second metal material(s) 760 can include materials similar to those infirst metal material(s) 740.

A second dielectric material 770 can be formed overlying second metalmaterial(s) 760 and at least one portion of first dielectric material750. Second dielectric materials 770 can include materials found in thefirst dielectric material mentioned previously. At least a third metalmaterial 780, which can include similar materials used in the metalmaterials mentioned previously, can be formed overlying at least aportion of second dielectric material 780. At least one passivationmaterial 790 can then be formed overlying third metal material(s) 780and second dielectric material 770. Passivation material(s) 790 caninclude dielectric materials, oxide materials, or silicon materials, orother materials or combinations thereof.

FIG. 8 is a simplified side diagram of a sensor device or electronicdevice according to an embodiment of the present invention. This diagramis merely an example, which should not unduly limit the scope of theclaims herein. One of ordinary skill in the art would recognize manyother variations, modifications, and alternatives. As shown, device 800includes a substrate 810, at least one application specific integratedcircuit (ASIC) material 821, at least one magnetic field sensing element820, and at least one magnetic field concentrator 830.

In an embodiment, substrate 810 can have a top surface region. In aspecific embodiment, substrate 810 can include a buried oxide (BOX)substrate. Substrate 810 can include a substrate-on-insulator (SOI)substrate. In another specific embodiment, substrate 810 can include anepitaxial (EPI) material. In further embodiments, substrate 810 can havea silicon, single crystal silicon, or polycrystalline silicon material.Substrate 810 can also include other materials and combinations thereof.

In an embodiment, substrate 810 can have at least one portion removed toform at least one lateral surface region, as shown by region 811. Theremoval of portion(s) of substrate 810 can include a wet etching, dryetching, or mechanical process. In a specific embodiment, the removal ofportion(s) of substrate 810 can include a deep reactive-ion etching(DRIE) process. The removal process can include other processes andcombinations thereof. In an embodiment, device 800 can include aninsulating material, which can be formed overlying at least one portionof the top surface region of substrate 810. In an embodiment, theinsulating material can be formed overlying at least one portion of thelateral surface region(s). ASIC material 821 can be formed overlying atleast one portion of substrate 810. In various embodiments, ASICmaterial 821 can include a variety of ICs related to signal conditionsand the like.

In an embodiment, magnetic field sensor element(s) 820 can be formedoverlying at least one portion of the top surface region. Magnetic fieldsensor element(s) 820 can include ordinary magneto-resistive (OMR)device(s), anisotropic magneto-resistive (AMR) device(s), giantmagneto-resistive (GMR) device(s), or tunnel junction magneto-resistive(TMR) device(s). The device(s) 820 can also be other types of magneticfield sensor device(s), sensors, or combinations thereof. In a specificembodiment, magnetic field sensor element(s) 820 can include thin filmdevices that can be deposited overlying at least one portion of the topsurface region. The thin film device(s) can be deposited by a sputteringprocess or an electric plating process. In a specific embodiment,magnetic field sensor element(s) 820 are formed through as a Wheatstonebridge, a half bridge, or a single element configuration. In anembodiment, magnetic field sensor element(s) 820 can include at leastone layer of dielectric material and/or metal material.

In an embodiment, magnetic field concentrator(s) 830 can be formedoverlying at least one portion of the lateral surface region(s). In anembodiment, magnetic field concentrator(s) 830 can also be spatiallyformed overlying at least one portion of the top surface region. In aspecific embodiment, magnetic field concentrator(s) 830 can include anickel-iron material. Magnetic field concentrator(s) 830 can alsoinclude other materials, compositions, and combinations thereof.Magnetic field concentrator(s) 830 can include permalloy material havinghigh permeability. In various embodiments, the material for magneticfield concentrators 830 may be the same as the material for magneticfield sensor elements 820, and may be deposited in the same operation.Subsequently, using conventional etching processes, magnetic fieldconcentrators 830 and magnetic field sensor elements 820 may then beseparated or defined. In a specific embodiment, magnetic fieldconcentrator(s) 830 can be formed via an electric plating process orsputtering process. Then, a passivation material can be formed overlyingat least magnetic field sensor element(s) 820.

FIG. 9 is a simplified side diagram of a sensor device or electronicdevice according to an embodiment of the present invention. Compared toFIG. 8, this diagram can represent another configuration of the devicecomponents. This diagram is merely an example, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.As shown, device 900 includes a substrate 910, at least one applicationspecific integrated circuit (ASIC) material 921, at least one magneticfield sensing element 920, and at least one magnetic field concentrator930. A detailed description regarding the elements of FIG. 9 can befound above in the description for FIG. 8.

FIG. 10 is a simplified cross-sectional diagram of a sensor device orelectronic device according to an embodiment of the present invention.Compared to the previous two figures, FIG. 10 can represent yet anotherconfiguration of the device components. This diagram is merely anexample, which should not unduly limit the scope of the claims herein.One of ordinary skill in the art would recognize many other variations,modifications, and alternatives. As shown, device 1000 includes asubstrate 1010, at least one application specific integrated circuit(ASIC) material 1021, at least one magnetic field sensing element 1020,and at least one magnetic field concentrator 1030. A detaileddescription regarding the elements of FIG. 10 can be found above in thedescription for FIG. 8.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. A method for fabricating a device for sensormagnetic fields, the method comprising: providing a substrate memberhaving a surface region; removing at least one portion of the substratemember; forming an integrated circuit (IC) layer overlying the substratemember; forming a first magnetic field sensor element comprising atleast a first material and configured to detect at least an x-axisdirection, the first magnetic field sensor element being operablycoupled to the IC layer; forming a second magnetic field sensor elementcomprising at least the first material and configured to detect at leasta y-axis direction, the second magnetic field sensor element beingoperably coupled to the IC layer; forming a third magnetic field sensorelement comprising at least the first material and configured to detectat least a z-axis direction, the third magnetic field sensor elementbeing operably coupled to the IC layer; forming at least one magneticfield concentrator spatially disposed overlying at least one portion ofthe substrate member, the magnetic field concentrator being formedwithin a vicinity of the third magnetic field sensor element; andforming at least one passivation material overlying the first, second,and third magnetic field sensor elements and the surface region; whereinall of the x-axis, y-axis, and z-axis directions are configured in amutually orthogonal manner.
 2. The method of claim 1 wherein thesubstrate member comprises a silicon material, a dielectric material, ora polymer.
 3. The method of claim 1 wherein the substrate member has atleast one portion patterned through a wet etching, dry etching, deepreactive-ion etching (DRIE), or mechanical process.
 4. The method ofclaim 1 wherein the IC layer comprises a silicon material, a dielectricmaterial, or a metal material.
 5. The method of claim 1 wherein the IClayer comprises at least one IC device.
 6. The method of claim 1 whereinthe first, second, and third magnetic field sensor elements compriseordinary magneto-resistive (OMR) devices, anisotropic magneto-resistive(AMR) devices, giant magneto-resistive (GMR) devices, or tunnel junctionmagneto-resistive (TMR) devices.
 7. The method of claim 1 wherein thefirst, second, and third magnetic field sensor elements comprise thinfilm device(s), the thin film device(s) being deposited overlying atleast one portion of the surface region.
 8. The method of claim 7wherein the thin film device(s) are deposited by a sputtering process.9. The method of claim 1 wherein the first, second, and third magneticfield sensor elements are formed as a Wheatstone bridges, half bridges,or single elements.
 10. The method of claim 1 wherein the first magneticfield sensor element is configured to be 45 degrees away from a crystaleasy axis direction.
 11. The method of claim 1 wherein the firstmagnetic field sensor element is configured to detect magnetic fields inthe x-axis direction.
 12. The method of claim 1 wherein the secondmagnetic field sensor element is configured to be −45 degrees away froma crystal easy axis direction.
 13. The method of claim 1 wherein thesecond magnetic field sensor element is configured to detect magneticfields in the y-axis direction.
 14. The method of claim 1 wherein thefirst and second magnetic field sensor elements are configured to besymmetrical across a crystal hard axis.
 15. The method of claim 1wherein the third magnetic field sensor is configured to a direction ona crystal hard axis or a crystal easy axis.
 16. The method of claim 1wherein the third magnetic field sensor element is aligned to the firstor second magnetic sensor element.
 17. The method of claim 1 wherein thethird magnetic field sensor element is configured to detect magneticfields in the z-axis direction, the third magnetic field sensor elementbeing able to detect vertical magnetic fields via the fieldconcentrator(s).
 18. The method of claim 1 further comprising aconductive strap disposed within a vicinity of the first, second, andthird magnetic field sensor elements.
 19. The method of claim 18 whereinthe conductive strap comprises a metal or metal alloy.
 20. The method ofclaim 1 wherein the field concentrator(s) comprise a nickel iron (NiFe)material or a nickel iron cobalt (NiFeCo) material.
 21. The method ofclaim 1 wherein the field concentrator(s) comprise permalloy materials,the permalloy materials having high permeability.
 22. The method ofclaim 1 wherein the field concentrator(s) are formed via anelectricplating process or a sputtering process.